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  • Haemophilus Ducreyi
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  • 1
    Language: English
    In: Journal of Bacteriology, 2014, Vol.196(23-24), p.4012(14)
    Description: Haemophilus ducreyi causes the sexually transmitted disease chancroid and a chronic limb ulceration syndrome in children. In humans, H. ducreyi is found in an abscess and overcomes a hostile environment to establish infection. To sense and respond to membrane stress, bacteria utilize two-component systems (TCSs) and extracytoplasmic function (ECF) sigma factors. We previously showed that activation of CpxRA, the only intact TCS in H. ducreyi, does not regulate homologues of envelope protein folding factors but does downregulate genes encoding envelope-localized proteins, including many virulence determinants. H. ducreyi also harbors a homologue of RpoE, which is the only ECF sigma factor in the organism. To potentially understand how H. ducreyi responds to membrane stress, here we defined RpoE-dependent genes using transcriptome sequencing (RNA-Seq). We identified 180 RpoE-dependent genes, of which 98% were upregulated; a major set of these genes encodes homologues of envelope maintenance and repair factors. We also identified and validated a putative RpoE promoter consensus sequence, which was enriched in the majority of RpoE-dependent targets. Comparison of RpoE-dependent genes to those controlled by CpxR showed that each transcription factor regulated a distinct set of genes. Given that RpoE activated a large number of genes encoding envelope maintenance and repair factors and that CpxRA represses genes encoding envelope-localized proteins, these data suggest that RpoE and CpxRA appear to play distinct yet complementary roles in regulating envelope homeostasis in H. ducreyi.
    Keywords: Hemophilus Infections – Causes of ; Sexually Transmitted Diseases – Risk Factors ; Transcription (Genetics) – Analysis
    ISSN: 0021-9193
    E-ISSN: 10985530
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  • 2
    Language: English
    In: Infection and immunity IAI, 2010, Vol.78(9), pp.3898-3904
    Description: Haemophilus ducreyi must adapt to the environment of the human host to establish and maintain infection in the skin. Bacteria generally utilize stress response systems, such as the CpxRA two-component system, to adapt to hostile environments. CpxRA is the only obvious two-component system contained in the H. ducreyi genome and negatively regulates the lspB-lspA2 operon, which encodes proteins that enable the organism to resist phagocytosis. We constructed an unmarked, in-frame H. ducreyi cpxA deletion mutant, 35000HPΔcpxA. In human inoculation experiments, 35000HPΔcpxA formed papules at a rate and size that were significantly less than its parent and was unable to form pustules compared to the parent. CpxA usually has kinase and phosphatase activities for CpxR, and the deletion of CpxA leads to the accumulation of activated CpxR due to the loss of phosphatase activity and the ability of CpxR to accept phosphate groups from other donors. Using a reporter construct, the lspB-lspA2 promoter was downregulated in 35000HPΔcpxA, confirming that CpxR was activated. Deletion of cpxA downregulated DsrA, the major determinant of serum resistance in the organism, causing the mutant to become serum susceptible. Complementation in trans restored parental phenotypes. 35000HPΔcpxA is the first H. ducreyi mutant that is impaired in its ability to form both papules and pustules in humans. Since a major function of CpxRA is to control the flow of protein traffic across the periplasm, uncontrolled activation of this system likely causes dysregulated expression of multiple virulence determinants and cripples the ability of the organism to adapt to the host. ; Includes references ; p. 3898-3904.
    Keywords: Bacterial Proteins -- Physiology ; Haemophilus Ducreyi -- Pathogenicity ; Protein Kinases -- Physiology;
    ISSN: 0019-9567
    E-ISSN: 10985522
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  • 3
    In: The Journal of Bacteriology, 2001, Vol. 183(19), p.5756
    Description: DNA sequence and Southern blot analyses were used to determine the genetic defect of a Haemophilus ducreyi pyocin-resistant lipooligosaccharide (LOS) mutant, HD35000R. The region of the HD35000R chromosome containing the suspected mutation was amplified, and sequence analysis detected a 3,189-bp deletion. This deletion resulted in the loss of the entire waaQ gene, another open reading frame that encodes a putative homolog to a hypothetical protein (HI0461) of H. influenzae, the gene encoding an argininosuccinate synthase homolog, and a change in the 3' sequence of the lgtF gene. Southern blot analysis confirmed that no genomic rearrangements had occurred. Isogenic LOS mutants and the respective complemented mutants were evaluated for susceptibility to pyocin C. The mutants expressing truncated LOS were resistant to lysis by pyocin C, and complementation restored sensitivity to the pyocin. We conclude that HD35000R is defective in both glycosyltransferase genes and that pyocin resistance is due to truncation of the full-length LOS molecule.
    Keywords: Mutation ; Haemophilus Ducreyi -- Drug Effects ; Lipopolysaccharides -- Metabolism ; Pyocins -- Pharmacology;
    ISSN: 0021-9193
    ISSN: 00219193
    E-ISSN: 10985530
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  • 4
    In: Infection and Immunity, 2002, Vol. 70(4), p.1667
    Keywords: Animals–Etiology ; Chancroid–Immunology ; Disease Models, Animal–Pathology ; Haemophilus Ducreyi–Immunology ; Humans–Pathogenicity ; Interferon-Gamma–Biosynthesis ; Macrophages–Immunology ; Neutrophils–Immunology ; Proteins–Biosynthesis ; Rabbits–Biosynthesis ; Tumor Necrosis Factor-Alpha–Biosynthesis ; Virulence–Biosynthesis ; Proteins ; Tumor Necrosis Factor-Alpha ; Interferon-Induced 56k Protein, Human ; Interferon-Gamma;
    ISSN: 0019-9567
    ISSN: 00199567
    E-ISSN: 10985522
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  • 5
    Language: English
    In: Journal of Infectious Diseases, June 1, 2008, Vol.197(11), p.1531(6)
    Description: 〈p〉Haemophilus ducreyi 35000HP contains a cluster of homologues of genes required for the synthesis of enterobacterial common antigen (ECA), suggesting that H. ducreyi may express a putative ECA-like glycoconjugate. WecA initiates the synthesis of ECA by transferring N-acetylglucosamine to undecaprenyl-P, to form lipid I. A wecA mutant (35000HPwecA) was constructed, and 5 volunteers were inoculated at 3 sites with fixed doses of 35000HP on one arm and at 3 sites with varying doses of 35000HPwecA on the other arm. 35000HPwecA caused pustules to form at 3 sites inoculated with a dose 2.5-fold higher than that of 35000HP. However, at sites inoculated with similar doses of 35000HP and 35000HPwecA, pustules developed at 46.7% (95% confidence interval [CI], 23.3%-70.0%) of 15 parent-strain sites and at 8.3% (95% CI, 0.01%-23.6%) of 12 mutant-strain sites (P = .013). Thus, the expression of wee A contributes to the ability of H. ducreyi to cause pustules in humans.〈/p〉
    Keywords: Hemophilus Infections -- Development And Progression ; Virulence (Microbiology) -- Research ; Chancroid -- Development And Progression ; Chancroid -- Research
    ISSN: 0022-1899
    E-ISSN: 15376613
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  • 6
    In: Infection and Immunity, 2007, Vol. 75(1), p.113
    Description: Haemophilus ducreyi is a gram-negative bacterium that is the causative agent of chancroid. Strain 35000HP has been well characterized and is representative of the majority of H. ducreyi strains. Strain 35000HP produces a lipooligosaccharide (LOS) that contains D-glycero-D-manno-heptose in the main oligosaccharide chain extension; the lbgB gene has been shown to encode the DD-heptosyltransferase. The lbgB gene is found in a gene cluster together with the lbgA gene, which encodes for the galactosyltransferase I. These two genes are flanked by two housekeeping genes, rpmE and xthA, encoding the ribosomal protein L31 and the exonuclease III, respectively. Recently, a second group of H. ducreyi strains have been identified. Strain 33921, a representative of the class II strains, produces an LOS that lacks DD-heptose in the oligosaccharide portion of its LOS. To better understand the biosynthesis of the DD-heptose-deficient 33921 LOS, we cloned and sequenced the corresponding lbgAB genomic region from strain 33921. Similar to strain 35000HP, the 33921 genome contains xthA and rpmE. However, between these two genes we identified genes encoding two putative glycosyltransferases that were not highly homologous to the 35000HP lbgAB genes. In this study, we demonstrate that the product of one of these genes encodes a galactosyltransferase. In addition, dot blot hybridization determined that 3 of 35 strains tested had the atypical transferases present, as did 4 strains characterized as class II strains by other criterion. These data indicate that the lbgAB genes can serve as one indicator of the classification of H. ducreyi strains.
    Keywords: Medicine ; Biology;
    ISSN: 0019-9567
    ISSN: 00199567
    E-ISSN: 10985522
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  • 7
    In: Infection and Immunity, 2005, Vol. 73(10), p.6727
    Description: Haemophilus ducreyi, the causative agent of chancroid, produces a lipooligosaccharide (LOS) which terminates in N-acetyllactosamine. This glycoform can be further extended by the addition of a single sialic acid residue to the terminal galactose moiety. H. ducreyi does not synthesize sialic acid, which must be acquired from the host during infection or from the culture medium when the bacteria are grown in vitro. However, H. ducreyi does not have genes that are highly homologous to the genes encoding known bacterial sialic acid transporters. In this study, we identified the sialic acid transporter by screening strains in a library of random transposon mutants for those mutants that were unable to add sialic acid to N-acetyllactosamine-containing LOS. Mutants that reacted with the monoclonal antibody 3F11, which recognizes the terminal lactosamine structure, and lacked reactivity with the lectin Maackia amurensis agglutinin, which recognizes alpha 2,3-linked sialic acid, were further characterized to demonstrate that they produced a N-acetyllactosamine-containing LOS by silver-stained sodium dodecyl sulfate-polyacrylamide gel electrophoresis and mass spectrometric analyses. The genes interrupted in these mutants were mapped to a four-gene cluster with similarity to genes encoding bacterial ABC transporters. Uptake assays using radiolabeled sialic acid confirmed that the mutants were unable to transport sialic acid. This study is the first report of bacteria using an ABC transporter for sialic acid uptake.
    Keywords: Transposons ; Galactose ; N-Acetyllactosamine ; Monoclonal Antibodies ; ABC Transporter ; Chancroid ; Agglutinins ; Lectins ; Infection ; Gel Electrophoresis ; Sialic Acids ; Lipooligosaccharides ; Haemophilus Ducreyi ; Genetics and Evolution ; Bacteria ; Microorganisms & Parasites;
    ISSN: 0019-9567
    ISSN: 00199567
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  • 8
    In: Infection and Immunity, 2002, Vol. 70(10), p.5887
    Description: Haemophilus ducreyi is the causative agent of chancroid, a sexually transmitted ulcerative disease. In the present study, the Neisseria gonorrhoeae lgtA lipooligosaccharide glycosyltransferase gene was used to identify a homologue in the genome of H. ducreyi. The putative H. ducreyi glycosyltransferase gene (designated lgtA) was cloned and insertionally inactivated, and an isogenic mutant was constructed. Structural studies demonstrated that the lipooligosaccharide isolated from the mutant strain lacked N-acetylglucosamine and distal sugars found in the lipooligosaccharide produced by the parental strain. The isogenic mutant was transformed with a recombinant plasmid containing the putative glycosyltransferase gene. This strain produced the lipooligosaccharide glycoforms produced by the parental strain, confirming that the lgtA gene encodes the N-acetylglucosamine glycosyltransferase.
    Keywords: Medicine ; Biology;
    ISSN: 0019-9567
    ISSN: 00199567
    E-ISSN: 10985522
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  • 9
    In: Infection and Immunity, 2004, Vol. 72(2), p.1143
    Description: The nucleotide sequence of pNAD1, a plasmid from Haemophilus ducreyi identified on the basis of its ability to confer NAD independence on Actinobacillus pleuropneumoniae and H. influenzae, has been determined. In addition to containing the nadV gene, the plasmid contains homologues of the rstR and rstA genes, genes encoding repressor and replication proteins, respectively, in the Vibrio CTX phi and the Vibrio RS1 element, suggesting a single-stranded bacteriophage origin for pNAD1. Tandem copies of the plasmid are integrated into the H. ducreyi 35000HP genome.
    Keywords: Haemophilus Ducreyi ; Vibrio ; Haemophilus Ducreyi ; Vibrio ; Genomes ; Nucleotide Sequence ; Plasmids ; Phages ; Genomes ; Nucleotide Sequence ; Plasmids ; Phages ; Nadv Gene ; Rstr Gene ; Rsta Gene ; Nadv Gene ; Rstr Gene ; Rsta Gene ; Plasmids ; Structure & Sequence ; Nad ; Rs1 Element ; Nad ; Rs1 Element ; Nad ; Rs1 Element ; Nadv Gene ; Rsta Gene ; Rstr Gene;
    ISSN: 0019-9567
    ISSN: 00199567
    E-ISSN: 10985522
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  • 10
    In: The Journal of Bacteriology, 2000, Vol. 182(8), p.2292
    Description: Haemophilus ducreyi is the etiologic agent of chancroid, a genital ulcer disease. The lipooligosaccharide (LOS) is considered to be a major virulence determinant and has been implicated in the adherence of H. ducreyi to keratinocytes. Strain A77, an isolate from the Paris collection, is serum sensitive, poorly adherent to fibroblasts, and deficient in microcolony formation. Structural analysis indicates that the los of strain A77 lacks the galactose residue found in the N- acetyllactosamine portion of the strain 35000HP los as well as the sialic acid substitution. From an H. ducreyi 35000HP genomic DNA library, a clone complementing the defect in A77 was identified by immunologic screening with monoclonal antibody (MAb) 3F11, a MAb which recognizes the N-acetyllactosamine portion of strain 35000HP LOS. The clone contained a 4-kb insert that was sequenced. One open reading frame which encodes a protein with a molecular weight of 33,400 was identified. This protein has homology to glycosyltransferases of Haemophilus influenzae, Haemophilus somnus Neisseria species, and Pasteurella haemolytica. The putative H. ducreyi glycosyltransferase gene was insertionally inactivated, and an isogenic mutant of strain 35000HP was constructed. The most complex los glycoform produced by the mutant has a mobility on sodium dodecyl sulfate-polyacrylamide gel identical to that of the los of strain A77 and lacks the 3F11- binding epitope. Structural studies confirm that the most complex glycoform of the LOS isolated from the mutant lacks the galactose residue found in the N-acetyllactosamine portion of the strain 35000HP LOS. Although previously published data suggested that the serum-sensitive phenotype of A77 was due to the los mutation, we observed that the complemented A77 strain retained its serum-sensitive phenotype and that the galactosyltransferase mutant retained its serum- resistant phenotype. Thus, the serum sensitivity of strain A77 cannot be attributed to the galactosyltransferase mutation in strain A77.
    Keywords: Haemophilus Ducreyi ; Chancroid ; Genetic Analysis ; Etiology ; Virulence ; N-Acetyllactosaminide a-1,3-Galactosaminyltransferase ; Genetics and Evolution;
    ISSN: 0021-9193
    ISSN: 00219193
    E-ISSN: 10985530
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